نتایج جستجو برای: O3

تعداد نتایج: 7332  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه اراک - دانشکده علوم پایه 1389

چکیده : دراین پایان نامه پس از مقدمه که شامل مروری بر روش های شیمی محاسباتی است، دو موضوع زیر مورد بررسی قرار گرفت: *انرژی پایداری، دانسیته ی الکترونی و سایر پارامترهای توپولوژیی کمپلکس های hclo4…o3 با استفاده از دو روش mp2 و m05-2x در سطح محاسباتیaug-cc-pvdz بررسی شدند. نتایج حاصل از این بررسی نشان می دهد که در روش mp2، 9 ساختار و در روشm05-2x ، 10 ساختار بدست آمده است. مقدار انرژی بعد از تص...

2011
ELAHE RAJAEIAN

Huisgen’s reaction of alkynes with Ozone (O 3 ), at its first step yielding carboxylic acids functional groups is, undoubtedly, an example of 1,3-dipolar cycloaddition reactions. Cycloadditions of 1,3-dipoles may occur by concerted mechanisms. The energy content in alkynes may be increased further by bending the normally linear triple bond, as in the small cycloalkynes. The strain energy in the...

2013
Yangyang Zhang Wen Shi Xiaohua Li Huimin Ma

Ozone (O3) has attracted much attention because of its key role in human health and disease, and its detection is of great importance for various biochemical studies as well as environmental evaluation. Here we develop a simple and practical spectroscopic off-on O3 probe based on resorufin and the specific reaction of but-3-enyl with O3. The probe shows an extremely low background spectroscopic...

2009
Zhan Chen Xiaoke Wang Zhaozhong Feng Qin Xiao Xiaonan Duan

This study was initiated to explore the effects of ozone (O3) exposure on potted wheat roots and soil microbial community function. Three treatments were performed: (1) Air with daily averaged O3 concentration of 4–10 ppb (control situation, CK), (2) Air plus 8 h averaged O3 concentration of 76.1 ppb (O3-1), and (3) Air plus 8 h averaged O3 concentration of 118.8 ppb (O3-2). In treatments with ...

2011
Jenny Klingberg

Ground-level ozone (O3) is a harmful air pollutant causing reduced crop yield and quality, reduced forest growth and negative effects on human health in large parts of the world. O3 is generally seen as a regional scale air pollution problem, but O3 concentration ([O3]) variation on a smaller geographical scale can be considerable. Knowledge of the size of this local scale variation and the und...

2015
Masahiro YAMAGUCHI Daiki HOSHINO Taisuke KONDO Ryohei SATOH Hidetoshi INADA Takeshi IZUTA

To evaluate the effects of O3 on the net photosynthetic rate in flag leaves of rice (Oryza sativa L.) based on stomatal O3 flux and reactive oxygen species (ROS) scavenging enzyme activities, the Japanese rice cultivar Koshihikari was exposed to O3 for 1 month after heading in O3-exposure chambers. During the exposure period, rice plants were exposed to charcoal-filtered air or O3 at 60 or 100 ...

2005
R. M. Doherty D. S. Stevenson W. J. Collins M. G. Sanderson

The impact of convection on tropospheric O3 and its precursors has been examined in a coupled chemistryclimate model. There are two ways that convection affects O3. First, convection affects O3 by vertical mixing of O3 itself. Convection lifts lower tropospheric air to regions where the O3 lifetime is longer, whilst mass-balance subsidence mixes O3-rich upper tropospheric (UT) air downwards to ...

Journal: :Journal of the American Chemical Society 2004
Timothy M Lesko A J Colussi Michael R Hoffmann

Hydrogen peroxide exalts the reactivity of aqueous ozone by reasons that remain obscure. Should H2O2 enhance free radical production, as it is generally believed, a chain mechanism propagated by (.OH/.O2-) species would account for O3 decomposition rates in neat H2O, HR-O3, and in peroxone (O3 + H2O2) solutions, HPR-O3. We found, however, that: (1) the radical mechanism correctly predicts HR-O3...

Journal: :Environmental pollution 2008
R Matyssek H Sandermann G Wieser F Booker S Cieslik R Musselman D Ernst

Upcoming decades will experience increasing atmospheric CO2 and likely enhanced O3 exposure which represents a risk for the carbon sink strength of forests, so that the need for cause-effect related O3 risk assessment increases. Although assessment will gain in reliability on an O3 uptake basis, risk is co-determined by the effective dose, i.e. the plant's sensitivity per O3 uptake. Recent prog...

2017
Kerem Teke Tayyar A Ozkan Oguz O Cebeci Hasan Yilmaz Muhammed E Keles Levend Ozkan Meltem O Dillioglugil Demir K Yildiz Ozdal Dillioglugil

Although non-muscle invasive bladder cancer (NMIBC) is widely seen in men, most laboratory studies of new intravesical therapies to prevent NMIBC have been conducted on female animals. In addition, ozone (O3) has been shown to be a beneficial agent as an intravesical application in the treatment of various disorders. In the current study, we evaluated the immunohistopathological and oxidative-a...

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